Summary
Workarounds
Disclaimer: There is currently no officially verified or comprehensive workaround for this issue. The only option would be to disable per-endpoint routes, but this will likely cause disruptions to ongoing connections, and potential conflicts if running in cloud providers.
Acknowledgements
The Cilium community has worked together with members of the Northflank and Isovalent teams to prepare these mitigations. Cilium thanks @sudeephb and @Champ-Goblem for reporting the issue and to @smagnani96 and @julianwiedmann for helping with the resolution.
For more information
Anyone who believes a vulnerability affecting Cilium has been found is strongly encouraged to report it to the security mailing list at [email protected]. This is a private mailing list for the Cilium security team, and any such report will be treated as top priority. Please also address any comments or questions on this advisory to the same mailing list.
Impact
Ingress Network Policies are not enforced for traffic from pods to L7 Services (Envoy, GAMMA) with a local backend on the same node, when Per-Endpoint Routing is enabled and BPF Host Routing is disabled.
Per-Endpoint Routing is disabled by default, but is automatically enabled in deployments using cloud IPAM, including Cilium ENI on EKS (eni.enabled), AlibabaCloud ENI (alibabacloud.enabled), Azure IPAM (azure.enabled, but not AKS BYOCNI), and some GKE deployments (gke.enabled; managed offerings such as GKE Dataplane V2 may use different defaults). It is typically not enabled in tunneled deployments, and chaining deployments are not affected. In practice, Amazon EKS with Cilium ENI mode is likely the most common affected environment.
The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.
CVE-2026-33726 has a CVSS score of 5.4 (Medium). The vector is reachable from an adjacent network, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.17.14, 1.18.8, 1.19.2); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
This issue was fixed by #44693.
This issue affects:
- Cilium v1.19 between v1.19.0 and v1.19.1 inclusive
- Cilium v1.18 between v1.18.0 and v1.18.7 inclusive
- All versions of Cilium prior to v1.17.13
This issue is fixed in:
- Cilium v1.19.2
- Cilium v1.18.8
- Cilium v1.17.14
Frequently Asked Questions
- What is CVE-2026-33726? CVE-2026-33726 is a medium-severity incorrect authorization vulnerability in github.com/cilium/cilium (go), affecting versions < 1.17.14. It is fixed in 1.17.14, 1.18.8, 1.19.2. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
- How severe is CVE-2026-33726? CVE-2026-33726 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/cilium/cilium are affected by CVE-2026-33726? github.com/cilium/cilium (go) versions < 1.17.14 is affected.
- Is there a fix for CVE-2026-33726? Yes. CVE-2026-33726 is fixed in 1.17.14, 1.18.8, 1.19.2. Upgrade to this version or later.
- Is CVE-2026-33726 exploitable, and should I be worried? Whether CVE-2026-33726 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-33726 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-33726?
- Upgrade
github.com/cilium/ciliumto 1.17.14 or later - Upgrade
github.com/cilium/ciliumto 1.18.8 or later - Upgrade
github.com/cilium/ciliumto 1.19.2 or later
- Upgrade